1. Field of the Invention
The present invention relates to a method of protecting a broadcast frame, a terminal authenticating the broadcast frame, and an access point broadcasting the broadcast frame. More particularly, the present invention relates to a method of protecting a broadcast frame, a terminal authenticating the broadcast frame, and an access point broadcasting the broadcast frame to immediately authenticate a broadcast management frame (BMF) when receiving the BMF without a delay.
2. Description of Related Art
The Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a standard developed by the IEEE. Standards within the 802.11 family include IEEE 802.11, IEEE 802.11a, IEEE 802.11b, and IEEE 802.11i, among others.
Generally, in the IEEE 802.11i standard, a security mechanism for protecting only a data frame has been proposed. Protection of a management frame has not been considered. IEEE 802.11i does not provide authentications of broadcast data frame, while IEEE 802.11i provides full protection of unicast data frames.
FIG. 1 is a diagram illustrating an example of a network which lacks the ability to authenticate a broadcast frame, according to a related art.
An access point (AP) 101 on a network 100 may distribute a group transient key (GTK) to all stations (STA) 102 and 103 on the network 100 while processing. In this embodiment, the stations 102 and 103 may protect a broadcast frame by using the GTK.
However, the stations 102 and 103 may transmit the broadcast frame when impersonating that the stations 102 and 103 are the AP 101, since the stations 102 and 103 may not identify an origin of the broadcast frame.
The broadcast frame, that is, a management frame, is critical in terms of a network function. Accordingly, an authentication of a broadcast management frame (BMF) is required.
To overcome such disadvantage, there is a method of protecting a broadcast frame by using an asymmetric signature algorithm. However, high computational complexity of the algorithm makes the method unsuitable for wireless devices.
Also, a time efficient stream loss-tolerant authentication scheme (TESLA) is another method to overcome such disadvantage. However, according to the TESLA, a receiver may not instantly perform an authentication of BMFs, which causes a delay in the authentication. The TESLA will be described in detail in the detailed description of exemplary embodiments in the present invention.
Accordingly, there is a need for an improved method of protecting a broadcast frame, a terminal authenticating the broadcast frame, and an access point broadcasting the broadcast frame to immediately authenticate a BMF when receiving the BMF without a delay.